Electric switch



Jan. 21, 1941. ROSENFELD 2,229,592

ELECTRIC SWITCH Filed June 8, 1938 2 .52 bertEosenfeZd INVENTOR ATTORNEYS Patented Jan. 21, 1941 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to an electric switch for speed alarms adapted for use on automobiles to warn the driver when the speed of his car has exceeded a predetermined maximum.

A further object is to provide, in a warning signal system of this character, a resilient switch contact assembled with the speedometer pointer and adapted to make good electrical connection with an adjustably mounted switch contact on the speedometer dial so that the device will operate effectively when subjected to vibration and shocks and jars of rough conditions of service.

A further object is to provide a device of this character which will be formed of a few strong simple and durable parts, which will be inexpensive to manufacture and which may be easily installed on used cars as well as on cars in the process of manufacture.

With the above and other objects in view the invention consists of certain novel details of construction and combinations of parts hereinafter fully described and claimed, it being understood that various modifications may be resorted to within the scope of the appended claim without departing from the spirit or sacrificing any of the advantages of the invention.

In the accompanying drawing forming part of this specification,

Figure 1 is a front elevation of a speedometer equipped with switch contacts constructed in accordance with the invention.

Figure 2 is a fragmentary cross sectional view of the speedometer shown in Figure 1 and showing the switch contacts in elevation.

Figure 3 is a detail cross sectional view showing the resilient contact carried by the pointer in end elevation.

Figure 4 is a bottom plan view of the resilient contact carried by the pointer.

Figure 5 is a cross sectional view of the speedometer dial and showing the contacts in circuit closing position.

Figure 6 is a cross sectional view taken on the line 6-45 of Figure 1 showing the adjusting mechanism of the adjustable contact.

Figure 7 is a cross sectional view taken on the line l'l of Figure 1 showing one of the binding posts of the adjustable switch contact.

Referring now to the drawing in which like characters of reference designate similar parts in the various views, 4 designates a speedometer having a dial 5 and a pointer 6, these parts being conventional.

In carrying out the invention an arcuate slot 1 is formed in the dial concentric with the speed adjusting bolt II is passed through the plate 9 10 and through the slot 1, as best shown in Figures 5 and 6.

For adjusting the contact a segment gear I2 is pivoted between collars l3 on the shaft 8 of the pointer. .A spacing sleeve [4 is mounted on 15 the bolt between the base plate 9 and the segment gear. The segment gear meshes with a pinion l 5 which projects through a slot in the top of the speedometer housing and which is fixed to a shaft 16. The shaft is journaled in openings l1 formed in a housing 18 which is mounted on top of the speedometer housing. The shaft is equipped with a knob I9 through the medium of which the pinion may be rotated to swing the segment gear which latter carries with it the adjustable contact to any adjusted position longitudinally of the slot 1.

Each conductor bar I0 is provided with a respective binding post 20 which extends through the slot I and is insulated therefrom by a sleeve 2| of insulating material. The binding posts are connected to flexible and extensible insulated circuit wires 22 which are anchored at the outer ends to the rear face of the dial by'screws 23. The circuit Wires are connected in series with the vehicle battery 24 and an alarm device 25 such as a bell.

The movable switch contact is fixed to the pointer 6 of the speedometer and comprises a 4 preferably formed of bolts are passed through the ends of the mica strips and clamp the strips together. A jumper Wire 29 connects the bolts together and bridges the conductor bars [0 of the adjustable switch contact when the contact points 28 are in circuit closing position, as best shown in Figure 5.

The jumper wire 29 is formed of spring material to hold the mica strips 26 in arched form. The resiliency of the strips permits of the strips yielding as the contact points 28 pass onto and off of the bars [8 of the adjustable switch contact.

In operation assuming that the predetermined speed limit not to be exceeded is 45 miles, the base 9 of the adjustable switch contact is set at the 45 mile speed indicating position on the dial. As the speed of the vehicle increases and reaches the 45 mile limit the pointer will be in a position to dispose the contact points 28 in circuit closing position upon the conductor bars Ill and close the alarm circuit at this point to energize the alarm bell. Thus the operator need not change the focus of his eyes when driving, to read the speedometer at close range, as each time the predetermined speed limit is reached the warning bell will sound.

It is not intended to limit the application of the invention to use on automobiles since the scope of the invention extends to any machine or apparatus for indicating when certain predetermined limits have been passed, such as pressure, as in a boiler, or of speed ina locomotive or airplane as well as for tanks such as used for storage of oil in heating systems, and other apparatus.

From the above description it is thought that the construction and operation of the invention will be fully understood without further explanation.

What is claimed is:

In switch mechanism, a dial, a pair of spaced switch contacts adjustable as a unit in a directioncircumferentially of the dial, a pointer on the dial swingable in a path to pass over the fixed contacts, a pair of transversely disposed mica strips secured at their centers to the pointer on opposite sides thereof, a pair of contact bolts passed through the ends of the strips and clamping the strips together, and a wire connected at the ends to the bolts and. insulated from the pointer by said strips, said wire and said bolts forming a bridging switch contact co-acting with the fixed contacts in circuit closing position when the pointer arrives at a position between the fixed contacts.

ALBERT ROSENFELD. 

